Back-country splitboarding is a popular sport with a dedicated following. When fully assembled, a splitboard looks like a snowboard, but can be taken apart to form a pair of skis. The right and left “skis” of a splitboard are asymmetrical; i.e., they are the mirror halves of a snowboard—longitudinally cut (or “split”), and typically have the sidecut (i.e. nonlinear long edges) and camber of snowboards. When worn separately as a pair of skis the rider can tour cross-country and climb through soft snow more quickly than by hiking. By joining the ski halves together, the rider descends as if riding a snowboard. The rider's stance in the snowboard riding configuration is sideways on the board, with legs spread for balance.
Because of the combination of functions, where the splitboard is sometimes used for skiing and other times for snowboarding, a great deal of ingenuity has been required in developing boot bindings that can be used in both “touring mode”, where the skis are used separately, and “ride mode”, where the boot bindings form part of a rigid union between the two ski halves. In both cases, the boot binding may include straps or bails, a heel or toe riser, a heel cup, a highback, and so forth to comfortably secure the boot to the board with a suitable degree of stiffness. Most modern riders use soft boots and flex at the knees and ankles to shift their weight and maneuver the board. The earliest patent applications on splitboards were filed by Ueli Bettenman starting in about 1988, and include Intl. Pat. Nos. CH681509, CH684825, German Gebrauchsmuster DE9108618 and EP0362782B1. In addition to the basic splitboard concept, these patents include drawings of splitboard bindings, both of a slidingly engageable rail type and a rotational clamping type, the bindings serving to secure the rider's boots to the skis in ski mode and the snowboard in ride mode. The earliest efforts at commercialization were made by Snowhow (Thalwil, CH) in Europe, and with the collaboration of the Fritschi brothers, Nitro Snowboards USA out of Seattle in the early 1990's. The Nitro snowboard binding consists of two slider tracks that join paired stationary flanged blocks mounted crosswise on each of the ski members. The binding bails are provided on a second plate which is hinged at the toe on the slider track and can be locked at the heel, thus enabling free heel ski mode when mounted parallel to the long axis of the ski members and ride mode when mounted crosswise. Supplemental stabilizers to hold the tips of the ski members together in ride mode include pairs of buckles.
Also an early contributor was Stefan Schiele, who filed Intl. Pat. Publication WO 98/17355 in 1996 on a three-part board joined by a rigid crosspiece at each foot, each crosspiece engaging three elevated pins with rotatable locking elements and having mating hooks at the ends of the boards. In ski mode, the skier carries the middle piece strapped to his backpack. Commercialization of this product, known as “System T3” continues.
Subsequently, Voile Manufacturing of Salt Lake City filed for a patent on an improved splitboard binding interface. U.S. Pat. No. 5,984,324 describes a slider track with insertable toe pivot pin for each foot, the slider track joining pair of “pucks” mounted on each ski member when mounted crosswise and also serving as a pivotable member for free heel touring. This innovation resulted in substantial growth of interest in splitboarding in the United States and has had worldwide impact on the sport.
Ritter, in U.S. Pat. Nos. 7,823,905, 8,226,109 and in US Pat. Appl. Publ. No 2013/025395, disclosed a stiffer, lower and lighter binding for spanning pucks mounted crosswise on the splitboard. The lightweight binding includes a toe pivot for free heel skiing and touring and has gained popularity among soft boot riders. These bindings are being commercialized by Spark R&D of Bozeman Mont. Maravetz, in U.S. Pat. No. 6,523,851, abandoned the rail-type binding in favor of a clamp designed to engage a pair of semi-circular flanged mounting blocks, one pair under each foot in ride mode. The two mounting blocks conjoin as a circle on which the jaw mechanism can be adjusted to suit the foot angle of the rider. Boot bindings are attached to the upper surface of the clamp member. Interestingly, the jaw of the clamp operates to tighten itself against the board and pull the two ski members together. However, the complexity of the mechanism is a disadvantage in that impacted snow tends to interfere with its operation. The clamp is provided with a built in toe pivot mechanism that is used in ski mode. The board is stabilized with front and rear hooks that join the ski members.
U.S. Pat. No. 8,033,564 to Riepler is under commercialization by Atomic (Altenmarkt Im Pongau, AT). The Atomic splitboard binding interface uses a rotating plate that engages four mushroom pins affixed to the ski members under each of the rider's feet. The rotating plate also operates a locking device for engaging a crampon tool. The internal workings are mounted between two plates that make up the body of the binding. The built-in toe pivot pin is spring-loaded in a sealed cylinder and engages a toe pivot cradle in ski mode. Ride mode configuration is stabilized by front and rear buckles and tip hooks. The ski members are unique in that they are shaped with a pointed downhill tip and a rounded tail. A well-known drawback of this interface is the need for a special spanner tool to transfer the binding between ski mode to ride mode.
U.S. Pat. Publ. No. US2010/0102522 to Kloster discloses two binding interface systems that appear to combine a number of features, including buckles and hooks for stabilizing the ski tips in ride mode. The Kloster binding is commercialized by Karakoram (North Bend, Wash.). In ski mode, a non-detachable axle at the toe is engaged by a pair of jaws operated by a release lever built into the toe pivot cradle. To disengage the toe axle from the pivot cradle, the rider lifts his boot heel and reaches under his foot to pull up the release lever (or removes the boot and reaches through the binding). A doubly-hinged linker arm couples the rotation of the release lever and the disengagement of the locking jaw.
In ride mode, the toe end is affixed to a pair of tabs mounted on a first ski member and a side lever arm operated by the rider causes extendable rods at the heel end to engage brackets mounted to the second ski member. As the side arm lever is rotated and locked, the two ski members are pulled together. The ride mode engaging system is sealed in a gear box to prevent snow entry, which would jam the workings. In ski mode, the toe end engages a toe pivot interface and requires its own lever-operated clamping mechanism. The use of two separate mechanisms for the toe pivot and ride mode interfaces adds complexity and weight.
Thus, there is a need in the art for a splitboard binding interface that overcomes the above disadvantages and provides the further improvements as will be apparent from the disclosure contained herein.